A widely-used approach for extended object tracking is based on random matrices, where the scattering matrix, i.e., measurement spread, is used to update a symmetric positive definite random matrix representing an elliptic extent. However, for lidar data, a mismatch between the assumed measurement model and observed data hinders the estimation quality of the method. We propose adaptions to the random matrix approach in order to facilitate the application for tracking a rectangular extended object based on contour measurements. Specifically, we derive a suitable scaling factor for the scattering matrix of measurements in this setting. Furthermore, we propose a simple yet effective estimation scheme for the target center, adapting the shape estimate accordingly. The resulting algorithm closely follows the framework of the random matrix approach. A detailed comparison with a variety of state-of-the-art trackers is carried out in a simulation based on real-world lidar parameters, confirming the effectiveness of the approach.

A novel concept for indoor self-localization based on rotating artificial landmarks with known locations using short-range radar is proposed. First, a processing pipeline for extracting range and angle measurements to the landmarks from a raw radar image is introduced, which consists of a neural network for distance estimation and a basic angle-of-arrival estimator. Second, a particle filter for tracking the pose based on the range and angle measurements is developed. Due to the ability of radar to measure range rate, i.e., the velocity in the direction of a detection, it is possible to robustly detect and localize rotating landmarks with the help of their micro-Doppler pattern. In this way, localization is possible even under difficult conditions (e.g., light changes). Experiments with a wheeled mobile robot and common office fans as landmarks demonstrate the effectiveness of the approach for indoor localization.

Successful tracking of an extended object requires accurate estimation of the target’s shape. In order to evaluate the estimation performance of such tracking algorithms, the target shape must be incorporated by a suitable metric or score. In this context, a common task is to determine a consolidated scalar score for the estimation accuracy across a set of different target types. We highlight problems exhibited by existing scores in this case, particularly if the data set consists of objects of diverse sizes. To this end, we focus on elliptical targets. Furthermore, we present a scale-invariant adaption of the commonly used Gaussian Wasserstein Distance, which does not suffer from the highlighted problem.

Recursive estimation of the orientation and spatial extent of an object from sparse measurements is a challenging yet crucial problem. To this end, we propose a problem-tailored particle filter that employs a special importance density for efficient sampling from high likelihood regions. This importance density is obtained with the help of a suitable analytic method for determining the length and width of the object. Due to the geometric meaning of the state vector, a consolidated estimate from the individual particles is obtained based on the Gaussian Wasserstein distance. The resulting filter can be employed with different analytic methods, and is found to improve estimation accuracy beyond state-of-the-art algorithms in a challenging scenario. Especially for low measurement rates, the proposed filter yields improved results compared to the reference methods.

The aeroelastic behaviour of aircraft is parameter variant. Changing flight conditions, such as e.g. flight velocity and altitude may change the vibration damping. When the vibration damping becomes zero or negative, self-excitation of the vibration occurs, called flutter. Modal parameter identification can be applied to extract eigenfrequencies and damping ratios based on e.g. acceleration data. In order to avoid flutter, modal parameters can be identified in flight testing of a new aircraft type close to real-time using optimized algorithms. Real-time identification of modal parameters has significant uncertainties, especially with respect to damping ratios. Those uncertainties cannot be calculated, but qualitatively estimated. In this study, a Kalman filter tracking is applied to reduce the uncertainties of modal parameter monitoring of aircraft. Since the process noise of such a system is impossible to foresee and is expected to change throughout a flight, the process noise is adapted with respect to the innovation and changing flight conditions. This context-aware adaptive Kalman filter is tested on data from a simulated aeroelastic model as well as on real flight test data of a small-scale fixed-wing UAV. The results show significant reduction of the identification uncertainties for both simulated and real data.

Multi-sensor fusion can improve environment perception, e.g., by increasing the field of view in collective perception, where intelligent vehicles communicate. Track-to-track fusion in a collective perception scenario makes it necessary to associate tracks from multiple sensors. Especially in settings with many sensors that have limited field of view, track-to-track association can be quite challenging. In this work, we develop a stochastic optimization-based approach for an arbitrary number of sensors with a limited field of view, which utilizes a cluster likelihood to sample joint associations. The proposed method clearly outperforms a greedy approach and computes the most likely associations with only a few samples. We evaluate the approaches on simulated data in static and dynamic scenarios.

BACKGROUND: ImputAccur is a software tool to measure genotype-imputation accuracy. Imputation of untyped markers is a standard approach in genome-wide association studies to close the gap between directly genotyped and other known DNA variants. However, high accuracy for imputed genotypes is fundamental. Several accuracy measures have been proposed, but unfortunately, they are implemented on different platforms, which is impractical. RESULTS: -based indices can be derived from standard output files of imputation software. Sample/probe and marker filtering is possible. This allows e.g. accurate marker filtering ahead of data analysis. CONCLUSIONS: The source code (Python version 3.9.4), a standalone executive file, and example data for ImputAccur are freely available at https://gitlab.gwdg.de/kolja.thormann1/imputationquality.git .

In this work, we discuss and compare Kalman filter-based approaches for tracking an elliptic extended object parameterized with orientation and semi-axes lengths. The methods include an Extended Kalman filter (EKF) implementation of the Random Hypersurface Model (RHM) approach using a radial function, an EKF-based approach for the Multiplicative Error Model (MEM), called MEM-EKF*, and a method for tracking the semi-axes independently, the Independent Axes Estimation (IAE) approach. We discuss pros and cons of the methods and compare them in various scenarios with a maneuvering object.

In this paper, an implementation of an extended target tracking filter using measurements from high-resolution automotive Radio Detection and Ranging (RADAR) is proposed. Our algorithm uses the Cartesian point measurements from the target's contour as well as the Doppler range rate provided by the RADAR to track a target vehicle's position, orientation, and translational and rotational velocities. We also apply a Gaussian Process (GP) to model the vehicle's shape. To cope with the nonlinear measurement equation, we implement an Extended Kalman Filter (EKF) and provide the necessary derivatives for the Doppler measurement. We then evaluate the effectiveness of incorporating the Doppler rate on simulations and on 2 sets of real data.

In this paper, a plain data-driven and simulation-based approach to object tracking is investigated. The basic idea is to use the probabilistic model of the tracking problem to simulate a large amount of state and observation sequences. Both are fed into a regression algorithm that learns a mapping from the observations to the states. In particular, we consider random forest regression and apply it to an object tracking problem using bearing-range measurements. The performance of the random forest tracking is compared to a Kalman smoother and particle filter.